TITROMETRIC METHOD FOR DETERMINING MASS PORTION OF MAJOR SUBSTANCE OF BETA-CHLOROVINYLARSONIC ACID

摘要

FIELD: analytical methods.;SUBSTANCE: invention relates to analysis of non-biological materials with chemical methods and can find use when solving tasks concerning environmental control on chemical weapon destruction objects. Method of determining mass portion of major substance of beta-chlorovinylarsonic acid in aqueous solutions comprises dissolving sample of beta-chlorovinylarsonic acid having mass 0.1-0.3 g in 50 mL water, to which two drops of 0.1% water-alcohol solution of phenolphthalein is added as indicator. Solution is titrated with 0.1 N sodium hydroxide solution to rose coloration and mass portion of major substance is calculated in terms of following equation: % (mass portion of major substance) = [(V₁-V₂)*K*0.00932135*100]/q, where V₁ is volume of 0.1 N sodium hydroxide solution utilized for titration of weighed sample of beta-chlorovinylarsonic acid, cm³; V₂ is volume of working solution utilized for titration of blank sample and decomposition of indicator, cm³; K is correction factor for titer of sodium hydroxide solution (K=1 when standard titer is used); 0.00932135 is quantity of beta-chlorovinylarsonic acid equivalent to 1 cm³ of 0.1 N sodium hydroxide solution, g/cm³, and q is mass of beta-chlorovinylarsonic acid sample. As measurement result, arithmetic mean of two parallel measurements is taken, wherein permissible deviation between the two measurements has not to exceed ±1%.;EFFECT: increased accuracy and simplified analytical procedure.;1 tbl